“Business has spent centuries making buying really easy,” says [Shareable’s Neal] Gorenflo. “We’re just at the beginning of making sharing easy.”

Gorenflo is a leading proselytizer of a global trend to make sharing something far more economically significant than a primitive behavior taught in preschool. Spawned by a confluence of the economic crisis, environmental concerns, and the maturation of the social web, an entirely new generation of businesses is popping up. They enable the sharing of cars, clothes, couches, apartments, tools, meals, and even skills. The basic characteristic of these you-name-it sharing marketplaces is that they extract value out of the stuff we already have. Many of these sites depend on millennials disenchanted by the housing bubble and the banking crisis, or uninterested in traditional icons of success such as house or auto ownership. But the number of people who have quietly begun tapping in is impressive: Already, more than 3 million people from 235 countries have couch-surfed, while 2.2 million bike-sharing trips are taken each month. Contends Rachel Botsman, coauthor of the recently published What’s Mine Is Yours: The Rise of Collaborative Consumption: “This could be as big as the Industrial Revolution in the way we think about ownership.”